Re: [PATCH nf-next v4 00/10] netfilter: nft_bitwise: shift support

[Pablo Neira Ayuso <pablo@netfilter.org>]

On Wed, Jan 15, 2020 at 09:32:06PM +0000, Jeremy Sowden wrote:
> The connmark xtables extension supports bit-shifts.  Add support for
> shifts to nft_bitwise in order to allow nftables to do likewise, e.g.:
> 
>   nft add rule t c oif lo ct mark set meta mark << 8 | 0xab
>   nft add rule t c iif lo meta mark & 0xff 0xab ct mark set meta mark >> 8
> 
> Changes since v3:
> 
>   * the length of shift values sent by nft may be less than sizeof(u32).
> 
> Changes since v2:
> 
>   * convert NFTA_BITWISE_DATA from u32 to nft_data;
>   * add check that shift value is not too large;
>   * use BITS_PER_TYPE to get the size of u32, rather than hard-coding it
>     when evaluating shifts.

Series applied, thanks.

I made a few updates:

* Replaced -EINVAL by -EOPNOTSUPP in case NFTA_BITWISE_OP is not
  supported. -EINVAL is usually reserved to missing netlink attribute /
  malformed netlink message (actually, you can find many spots where
  this is a bit overloaded with different "meanings", but just trying
  to stick to those semantics here).

* Replaced:

        return nft_bitwise_init_bool(priv, tb);

  by:

        err = nft_bitwise_init_bool(priv, tb);
        break;
  }

  return err;

  in a few spots, I hope I did not break anything.

I tend to find that easier to read today, minor things like this are
very much debatable.

Thanks.